remove fptr(this); You call qthread's Execute() from your main thread and you are waiting on a condition variable.

To: boost-users@lists.boost.org From: Viatcheslav.Sysoltsev@h-d-gmbh.de Date: Fri, 15 Apr 2011 15:18:06 +0200 Subject: Re: [Boost-users] [thread] : pause/resume thread

...

Hi All, I have just started learning boost. I want my thread to support following functions Pause(); Resume(); Stop();. I have come up with following code, which ends up as dead lock. Can some one please guide me as how to achieve the desired functionality. Would really appreciate any help. Thanks. Kaz class qthread { public: boost::thread* mThread; boost::condition_variable mCond; boost::mutex mMutex; bool mExit; qthread(): mExit(false) { // create function pointer to local Execute function boost::function fptr = &qthread::Execute; fptr(this); you call Execute() here in the main thread

...

// pass on function pointer along with this reference to boost thread boost::thread th0( fptr, this); // assign temp thread to local variable mThread = &th0; }

and now your th0 is destroyed leaving invalid pointer. Strange, I thought gcc has already learned to warn about such stuff, but I don't get any warning with gcc 4.3.2 here even with -Wall

...

mCond.wait(lock); //<< DEAD LOCK

It's not a dead lock, don't swear with so scary words ;). If you'd debug the program, you see you are still having only one thread by the time.

-- Slava

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

inside qthread contructor, copy just the following and you are good to go. mThread = new boost::thread(bind(&qthread::Execute, this));

Pardon my ignorance here, but I assume I also have to manually delete the mThread then ?,if not, when qThread object goes out of scope, who ll remove it, (or take its ownership) ? 2011/4/15 bit bit

inside qthread contructor, copy just the following and you are good to go.

mThread = new boost::thread(bind(&qthread::Execute, this));

------------------------------ Date: Fri, 15 Apr 2011 11:06:56 +0100 From: sfx810@googlemail.com To: boost-users@lists.boost.org Subject: [Boost-users] [thread] : pause/resume thread

Hi All, I have just started learning boost. I want my thread to support following functions Pause(); Resume(); Stop();. I have come up with following code, which ends up as dead lock. Can some one please guide me as how to achieve the desired functionality. Would really appreciate any help. Thanks. Kaz class qthread { public: boost::thread* mThread; boost::condition_variable mCond; boost::mutex mMutex; bool mExit; qthread(): mExit(false) { // create function pointer to local Execute function boost::function fptr = &qthread::Execute; fptr(this); // pass on function pointer along with this reference to boost thread boost::thread th0( fptr, this); // assign temp thread to local variable mThread = &th0; } void Resume() { mMutex.unlock(); mCond.notify_all(); } void Stop() { mThread->interrupt(); mExit = true; Resume(); } void Pause() { // todo } virtual void Execute() { std::cout<<"Entering thread Execution"<boost::mutex lock(mMutex); mCond.notify_all(); mCond.wait(lock); //<< DEAD LOCK int i = 0; while ( !mExit ) { try { while ( 1 ) { std::cout<<"Executing thread, cycle i = "<<++i<http://lists.boost.org/mailman/listinfo.cgi/boost-users

_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users